To address one of the present needs of the Division of AIDS, the Efficacy Trials Branch (ETB) in the Vaccine and Prevention Research Program (VPRP) of the Division of AIDS, National Institute of Allergy and Infectious Diseases (NIAID), plans to continue to maintain a Statistical and Clinical Coordinating Center (SACCC) for providing: (1) statistical and research design expertise for the Women and Infants Transmission Study (WITS); (2) statistical analyses and data management for the WITS; (3) central coordination of the systems for laboratory specimen processing, storage, and retrieval supported by the ETB through existing contracts and subcontracts to keep track of the type and amount of specimens available in the national repository; (4) general statistical support for special projects of the ETB; and (5) educational and training activities involving statistical and data management issues for these studies. Specific responsibilities of the Contractor are described in the Work Statement.